Electric heater unit



May 27, 1924.

T. A. REID ELECTRIC HEATER UNIT Filed Sept. 23, 1922 2 Sheets-Sheet 1 Fig. 1.

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ATTORNEY ELECTRIC HEATER UNIT Filed Sept. 23, 1922 2 Sheets-Sheet 2 24 2| Z3 WITNESSES:

ATTORNEY Patented May 27, 1924.

UNITED STATES PATENT OFFICE.

THOMAS A. REID, F WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRIC HEATER UNIT Application filed September 23. 1922. Serial No. 590,212.

' quickly inserted in, and removed from, the

furnace structure.

In racticing my invention, I provide a plurality of co-extensive sets of relatively thin, refractory, electric-insulating plates located in abutting relation and the plates of one set having mte ral means for maintaining said sets of p ates in spaced-apart relation. I provide a pair of spacing-bars located adjacent the free longitudinal edges of said sets of plates and a plurality of pairs of relatively narrow supporting members located in face-to-face relation relatively to each other and having their ends secured to the respective spacing bars. Means secured to the end pairs of supporting members prevent the longitudinal movement of the plates. In the drawings,

Figure 1 is a view, in vertical lateral section, of an electric-resistance furnace comprising the device embodying my invention;

Fig. 2 is a diagrammatic view of a portion of a heating element embodying my invention;

Fig. 3 is a view, in front elevation, of a heating element embodying my invention; and

Fig. 4: is a view, in end elevation, of the device illustrated in Fig. 3.

Referring more particularly to Fig. 1 of the drawings, I have there illustrated an electric-resistance furnace 11 comprising a plurality of outer walls, floor and ceiling 12 constituted by a plurality of bricks or blocks of a suitable refractory heat-insulating material. An inner lining 13. for the outer walls 12 may comprise a plurality of. bricks or blocks of a suitable high-temperature resistance material. The inner-lining walls 13 are suitably spaced apart to provide a furnace chamber 14 of'any suitable or desired contour and dimensions. Within the furnace chamber 14 are located a plurality of heating elements 15 which are to be hereinafter described more in detail. These heatin elements may be located adjacent the si e walls of the furnace and have their upper edges engaged by the inner ends of suitable clamping members 16, of substantially L-shape. The clampin or retaining members 16 may be constitute by bolts having one end thereof bent at substantially right angles thereto and have their outer ends threaded to permit of mounting thereon a nut 17 and a washer 18 to retain the member 16 and the upper edge of the heatmg element 15 in proper operative positions relatively to the furnace structure. One or more of the heating elements 15 may be located on the floor of the furnace, substantially as illustrated in Fig. 1 of the drawings.

The heating elements 15 comprise a plurality of relatively thin, refractory, electricinsulating plates 19 which have their edges located in abutting relation, a sufiicient number of the plates 19 being employed to cooperate, and be substantially co-extensive, with the depth of the furnace chamber. Each of the refractory plates 19 is provided with a plurality of rows of integral and relatively small spaced projections which are operatively alined thereon, both longitudinally and laterally of the plates. This construction is illustrated in one of the plates shown in Fig. 2 of the drawing and is more particularly disclosed and claimed in application, Serial No. 449,685, filed March 5, 1921, by O. A. Colby and myself, and assigned to the Westinghouse Electric & Manufacturing Company.

A resistor member 21, which is located as to engage the fiat surface of the plates 19 having the projections thereon, comprises a relatively heavy bar of a suitable resistance material, preformed to comprise a plurality of substantially straight, parallel-extending and end-connected convolutions, substantially as illustrated in Fig. 2 of the drawing. The.integral projections on that surface of the plates which s operatively engaged by the resistor member 21 serve to maintain the convolutions of the resistor member in their proper operative positions relatively to each other.

A second set of plates 19, substantially the same as the first set, is provided and are so located as to be co-extensive therewith,

spective spacing bars 21 by means of bolts 23.

and nuts 24, the bolts extending through the holes provided in the spacing bars. The members 22 are so located that they extend along the abutting edges of the two sets of plates 19, whereby the plates are retained in their proper operative positions within the skeleton frame and are prevented from lateral movement relatively thereto.

Means for preventing movement of the plates 19' longitudinally of the built-up heating element 15 may comprise a bolt 25 and a nut 26, located at the ends of the heating element and extending through holes at the middle of the length of the end pairs of'narrow supporting members, a tubular spacing member 27 being placed between the pair of supporting members. Any desired number of plates may be employed in each of the two sets, it being only necessary that the length of the pair of spacing bars 21 be made in accordance with the number of plates employed.

The lateral dimension of each of the plates 19 may be made substantially one-half that of the longitudinal dimension, an arrangement which permits of locating the plates 19 with their longer dimension extending longitudinally of the heating element 15, substantially as indicated by the broken line in Fig. 3 of the drawing. In this case, two of the plates 19 are placed in edge-abutting relation andextend so as to be operatively engaged by three pairs of the relatively narrow supportingmembers.

No means for bringing out the ends of the resistor member 21 to terminal members are shown, as any suitable or desired method of construction may be employed.

The heating elements embodying my invention may be easily and quickly assembled with any desired number of the thin plates to any desired overall dimension longitudinally of the heating element. The assembled heating elements may be easily and quickly mounted in, and removed from, the furnace chamber and provide a substantially protected resistor member therein.

Modifications in the system and arrangement and location of parts may be made within the spirit and scope of my invention,

and such modifications are intended to be covered by the appended claims.

I claim as'iny 1nvention:

1. In an electric-heating element, in combination, a plurality of co-extensive sets of relatively thin, refractory electrical insulating plates, the plates of each set being located in abutting relation. a resistor member located between said sets of plates, and a skeleton framework for holding said sets of plates in proper operative ositions relatively to each other, said ramework comprising spacing bars adjacent the free edges of said plates, and relatively narrow supporting members extendin on the outside of said plates between sald spacing bars and having their ends secured thereto.

2. In an electric-heating element, in combination, a skeleton frame comprising a pair of spacing bars and a plurality of spacedapart relatively narrow, supportin members having'their ends secured to sald spacing bars, a plurality'of sets of relatively thin, refractory electrical-insulating plates located between said supporting members, means integral with theplates of one set for maintaining the two sets of plates in spacedapart relation, and a resistor member located between said sets of plates.

3. In an electric-heating element, in combination, a skeleton frame comprising 'a pair of spacing bars and a plurality of spacedapart relatively narrow, supportin members having their ends secured to sa1d spacing bars, a plurality of sets of relatively thin, refractory, electrical-insulating plates located between said supporting members, means integral with the plates of one set for maintaining the two sets of plates in spacedapart relation, means secu'red between the end-supporting members for preventing movement of said refractory plates longitudinally of said heating element and a resistor member located between said sets of plates.

4. In an electric-heating element, in combination, a skeleton framework comprising a pair of parallel-extending and co-extensive spacing bars and a plurality of spaced-apart sets of relatively narrow supporting members, the supportin members of each set being located in face-to-face relation, with their ends secured to the spacing bars, on opposite sides thereof, a plurality of sets of relatively thin refractory electrical-insulating plates located between said supporting members, means integral with the plates of one set for spacing said sets of plates apart, means secured to the end .sets of securing members for preventing movement of said plates longitudinally of said heating element, and a resistor member located betwen said sets of plates,

5. In an electric-heating element, in combination, a skeleton framework comprising a pair of parallel-extending and co-extensive spacing bars and a plurality of spaced-apart sets of relatively narrow supporting members, the supporting members of each set being located in face-to-face relation with their ends secured to the spacing bars, on opposite sides thereof, a plurality of sets of relatively thin refractory electrical-insulating plates located between said supporting members, a resistor member comprising a plurality of substantially straight,

parallelextending end-connected convolutions located between said sets of plates, and a plurality of rows of integral and operatively alined projections on the plates of one set of plates for spacing said sets of plates apart and for maintaining the convolutions of said resistor member in proper operative positions relatively to each other.

In testimony whereof, I have hereunto subscribed my name this 16th day of September 1922.

THOMAS A. REID. 

